There is a site called "Ioverlander.com". This gives camping spots all over the world. This includes 8 spots in Afghanistan, 580 in Columbia, 819 in Peru etc. All of the Overlanders here use it. As noted earlier over half the folks here are, or have been Overlanders.
Another retired German couple showed up in a modern VW camper. They had electronic problems with engine and fortunately there is a modern VW dealershis in Cancun area. They shipped van on a container ship from Hamburg to Montevideo, Uruguay and spent 4 weeks as passengers. They have traveled up through Uruguay, Argentina, Bolivia etc. They said they boondocked a lot in Argentina, Bolivia and Peru.
Reed and Elaine